中级微观经济学选择,
中级微观经济学选择,
Hans has 27 dollars,which he decides to spend on x and y.Commodity x costs $16 per unit and commodity y costs $10 per unit.He has the utility function U(x; y) = 5x^2 + 2y^2 and he can
purchase fractional units of x and y.
(a) Hans will choose only x.(b) Hans will choose only y.
(c) Hans will choose some of each commodity,but more y than x.(d) Hans will choose some of each commodity,but more x than y.
答案为什么选B?不是根据MUx/MUy=Px/Py做么?
我做了一下,选择c,并且,x的数量0.854,y的数量1.336,的时候效用最大可是此时效用为7.2如果选b的话，效用为14.58.这是因为要检查角点解吗？抱歉，应该选择B，我给出的(x,y)是最小效用，你把约束函数和效用函数列一下，得到效用函数：U(x,y)=10.12X^2-17.28x+14.58其中x的范围是[0,1.6875]问题转成求该范围内效用最大值时，x的取值。二次函数对称轴为：x=0.854，x取值范围一半是0.84375，所以图像是左高右低，即在最左边，x=0时，取得效用最大。应该有更简洁的方法的，不过好多年没看过微经了，忘记了o(╯□╰)o来个好评啊，亲~